The impact of adsorption on the localization of spins in graphene oxide and reduced graphene oxide, observed with electron paramagnetic resonance

2017 ◽  
Vol 111 (8) ◽  
pp. 084102 ◽  
Author(s):  
Mateusz Kempiński ◽  
Patryk Florczak ◽  
Stefan Jurga ◽  
Małgorzata Śliwińska-Bartkowiak ◽  
Wojciech Kempiński
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Paramagnetic Resonance ◽  
Reduced Graphene ◽  
The Impact ◽  
Electron Paramagnetic

scholarly journals Tuning Properties of Partially Reduced Graphene Oxide Fibers upon Calcium Doping

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 957 ◽  
Author(s):  
Krzysztof Tadyszak ◽  
Jacek K. Wychowaniec ◽  
Karol Załęski ◽  
Emerson Coy ◽  
Łukasz Majchrzycki ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Chemical Properties ◽  
Fiber Axis ◽  
Paramagnetic Resonance ◽  
Physico Chemical ◽  
Reduced Graphene ◽  
Calcium Doping ◽  
Bulk Structures ◽  
Pulsed Electron Paramagnetic Resonance ◽  
Electron Paramagnetic

The arrangement of two-dimensional graphene oxide sheets has been shown to influence physico-chemical properties of the final bulk structures. In particular, various graphene oxide microfibers remain of high interest in electronic applications due to their wire-like thin shapes and the ease of hydrothermal fabrication. In this research, we induced the internal ordering of graphene oxide flakes during typical hydrothermal fabrication via doping with Calcium ions (~6 wt.%) from the capillaries. The Ca2+ ions allowed for better graphene oxide flake connections formation during the hydrogelation and further modified the magnetic and electric properties of structures compared to previously studied aerogels. Moreover, we observed the unique pseudo-porous fiber structure and flakes connections perpendicular to the long fiber axis. Pulsed electron paramagnetic resonance (EPR) and conductivity measurements confirmed the denser flake ordering compared to previously studied aerogels. These studies ultimately suggest that doping graphene oxide with Ca2+ (or other) ions during hydrothermal methods could be used to better control the internal architecture and thus tune the properties of the formed structures.

scholarly journals Supramolecular Structure of Polypropylene Fibers Extruded with Addition of Functionalized Reduced Graphene Oxide

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 910 ◽  
Author(s):  
Jan Broda ◽  
Janusz Fabia ◽  
Marcin Bączek ◽  
Czesław Ślusarczyk
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Supramolecular Structure ◽  
Nucleating Agent ◽  
Polypropylene Fibers ◽  
Fiber Structure ◽  
X Ray Scattering ◽  
Reduced Graphene ◽  
The Impact ◽  
Spun Fibers

An effective β-nucleating agent for polypropylene crystallization was obtained by the functionalization of reduced graphene oxide with calcium pimelate. The nucleating ability of the modified reduced graphene oxide (rGO-CP) was confirmed during non-isothermal crystallization. In further examinations, the rGO-CP was used as an additive to modify polypropylene fibers. The fibers were extruded in laboratory conditions. Gravity spun fibers containing three different concentrations of the rGO-CP and fibers taken at three different velocities were obtained. The supramolecular structure of the fibers was examined by means of calorimetric and X-Ray Scattering methods (DSC, WAXS, and SAXS). The considerable amount of β-iPP was obtained only in the gravity spun fibers. In the fibers extruded at higher velocities, the diminishing impact of the additive on the fibers structure was revealed. The changes observed in the fiber structure in connection with the impact of the additive on polypropylene crystallization was discussed.

scholarly journals Manufacturing and Evaluation of Mechanical, Morphological, and Thermal Properties of Reduced Graphene Oxide-Reinforced Expanded Polystyrene (EPS) Nanocomposites

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Tomasz Rydzkowski ◽  
Kazimierz Reszka ◽  
Mieczysław Szczypiński ◽  
Michał Marek Szczypiński ◽  
Elżbieta Kopczyńska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Carbon Nanoparticles ◽  
Bending Strength ◽  
Expanded Polystyrene ◽  
Thermal Conductivity Ratio ◽  
Reduced Graphene ◽  
Similar Density ◽  
The Impact

The aim of the present study is to examine the effect of the addition of carbon nanoparticles (σsp2 hybridization) on the mechanical properties of foamed polystyrene. In this work, we focus on the study of the impact of compressive stress, tensile strength, bending strength, thermal conductivity ratio (λ), and water absorption of expanded polystyrene (EPS) reinforced with reduced graphene oxide and graphite. The results were compared with pristine EPS and reduced graphene oxide-reinforced EPS. All the nanocomposite specimens used for testing had a similar density. The study reveals that the nanocomposites exhibit different thermal conductivities and mechanical properties in comparison to pristine EPS. The enhancement in the properties of the nanocomposite could be associated with a more extensive structure of elementary cells of expanded polystyrene granules.

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